Shear-bar for reinforced concrete construction.



APPLICATION FILED SEPT. 29, 1908.

Patented June 22. 1909.

hi m

lull

THE NORRIS PETERS COHIWASHINGTIJN, n, c,

CHARLES T. LINDSAY, OF PITTSBURG, PENNSYLVANIA.

SHEAR-BAR FOR REINFORCED CONCRETE CONSTRUCTION.

Specification of Letters Patent.

Patented June 22, 1909,

Application filed September 29, 1903. Serial No. 455,356.

To all whom it may concern:

Be it known that I, CHARLES T. LINDSAY, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Shear-Bars for Reinforced Concrete Construction, of which the following is a specification, reference being had therein to the accompanying drawings, forming part thereof.

My invention relates to reinforced-concrete and other cementitious constructions.

One object of my invention is to provide simple and effective means for rigidly binding the reinforcing frame together and resisting the shearing strains through the concrete flooring or beam without in any way weakening the reinforcing frame.

Another object is to render the resisting means selflocking against the pressure of the concrete, and adapted for use with different kinds and shapes of reinforcements.

Other objects are economy of manufacture, simplicity of construction, facility of assembling the parts, and efficiency of operation.

Other objects and advantages of my invention will appear from the following description.

I shall now describe my invention with reference to the accompanying drawings and shall thereafter point out my invention in claims.

Figure 1 is a side elevation, partly in section, of a span of a reinforcing frame broken away at the middle and embodying my invention. Fig. 2 is a transverse section on an enlarged scale taken on the broken line maz of Fig. 1 looking toward the right. Fig. 3 is a sectional elevation of a portion of the shear-bar taken on the line 1 g of Fig. 2 looking toward the left. the concrete being removed and the girder being shown in dotted lines to more clearly illustrate the locking angle. Fig. 4 is a detail plan view of a shear-bar twisted at the center, but in all other respects substantially the same as the bars shown in the previous figures.

In a span, such as is shown in Fig. 1, it is a matter of common knowledge that the shearing stress follows a line running from the top near the columns or supports toward the bottom at the center. In addition, therefore, to the usual reinforcing girders 1 and 2 at the bottom of the concrete beam, other reinforcements are needed, at the top near the ends and in the bottom at the middle. The girders 3 and A serve this purpose at theends and extend an equal distance each side of the columns or supports. Extra reinforcements may be laid in the bottom at the middle, supported by the cross-bonds 5 and 6, the former being shown in section. To hold this reinforcing frame rigidly and to resist the shearing strains, I connect the upper and lower girders by a series of steel bars 7. These bars are shown as Hat and provided with perforations or holes 8 to allow the bars to be passed on and form a connection be tween the corresponding upper 'and lower reinforcements. It is evident that the perforations or holes 8 may be of any shape to adapt the bar for use with any shaped girder or reinforcement commonly used.

To be the most effective, the shear-bars must extend between the reinforcements obliquely in a direction substantially perpendicular to the line of the shear, as shown in Fig. 1; the perforations or holes 8 are therefore punched straight through the bar perpendicular to the flat faces as shown, so that the bars will be self-locking on the girders and will not be pushed out of place by the pressure of the concrete, since the holes 8, being slightly longer than the height of the girder, fit about the girder at a looking angle. This angle is best illustrated 111 Fig. 8.

If it is desired, the shear-bars may, of course, be twisted at the center, as is shown in Fig. 4, to form a mechanical bond.

It will be'observed that with my invention I avoid punching holes in the girders, bending the bars, and other means commonly resorted to, which tend to weaken the construction. After my bars have been passed on the end of the girders and pushed to their places, the pressure of the concrete securely locks the whole structure, and nowhere is the strength of the fiber of the steel impaired.

It is obvious that various modifications may be made in the construction shown and above particularly described within the principle and scope of my invention.

I claim:

1. In reinforced concrete construction, the combination with the main members of shear bars connecting the main members and joined thereto at perforated port-ions fitting over the main members and having their longitudinal faces in planes transversely crossing the main members.

combination With the main members of' shear-bars adapted to connect the main members at an angle substantially perpendicular to the shearing force, the bars having flat perforated portions with their flat faces in' planes transversely crossing the main mem- I:

bers and having elongated perforations the Walls of Which are perpendicular to the flat faces, and being arranged to fit over the main members at a locking angle.

In testimony whereof I have afiixed my 26 signature in presence of two Witnesses.

CHARLES T. LINDSAY.

lVitnesses VIc'roR D. Bonsr,

BERNARD COWEN. ,5 

